Connection Problem with Windows 8

So I have recently bought civilization 4 with the beyond the sword expansion pack from steam. Everything runs very smoothly except when I want to play online. When I try to join my friends game or when i try to host a game, i get stuck in the contacting host screen and after a bit i will get a message saying connection to host timed out. This is very strange because it only happens to two of my friends. However if i were to join a game with another one of my friends i am able to join his game and he mine, but the other two friends wouldn't be able to join our game. So i spent sometimes reading the forums and i turned off all my firewalls. I use a windows 8 acer cpu with norton as my internet protection. Nothing has worked. Please tell me what i can do since i am using windows 8 alot of properties of windows 7 doesnt work with my cpu.

If you can connect with one of them, the the problem is probably not with the two of you. It is with the two who can't connect or be connected to. They need to adjust their computers or routers to allow the connections.